Len'alas lath'din.

Falon'Din and Fen'Harel have the second parts of their names capitalized.

Elgar'nan and Ghilan'nain do not.

I don't think this is a mistake.

Falon and Din are both their own words fully. Same thing with Fen and Harel.

Both Elgar and Ghilan are their own words fully, but nain is not. In fact, of the official canon words, nain doesn't even appear at all (yet) outside of Ghilan'nain; neither by itself nor within another word.

Nan could be a suffix if combined like vheNAN and may mean "centre" (apparently, according to Trick Weekes outside of canon sources)

However, I propose that because "nan" in Elgar'nan is not capitalized, it is not a full word by itself in Elgar'nan's name, but shortened. Possibly because the Evanuris only have 2/3 syllables in their "god names."

There is a bow in Inquisition which calls Elgar'nan "Sun's Death." And one of the words for death is "Dinan."

Cole

And you know, YOU KNOW, she looked Varric full in the face

Before A Slow Poison quest is completed, there's no banner hanging there.

If A Slow Poison quest is completed, Fletcher's banner can be seen next to their store. If the player saved Minrathous, it'll disappear later, along with Fletcher themselves.

After completing For the Love of Treviso quest, three banners of de Acutis (Neri and Noa's house) appear in the casino. I think it's because they were actively involved in that quest earlier.

And after completing A Time to Kill quest, the final two banners of Egrativi (Jacobus' new house) are hung.

Unlike Fletcher's banner, the city choice doesn't affect the others.

There's still some space left in the hub, but I don't know if that means there was supposed to be another banner here, or if it's just to make the crow statue at the entrance visible.

WIP Wednesday-

But it's interesting that the Ossuary is said to be Ghila'nain's old laboratory, where she experimented by making new creatures... And there's a Dread Wolf statue down there.